Stevia extracts are widely used as sweeteners and it is known that glycosides of terpenoids such as stevioside and Rebaudioside A function as sweet components. Recently, there has been progress in the analysis of sweet components contained in the stevia extract and studies on various steviol glycosides contained in the stevia extract have been conducted. For example, Patent Literature 1 proposes a technique for producing specific steviol glycosides (RebX).
Physiological effects of polyphenols have recently attracted attention due to the increase in health consciousness and the demand for polyphenol-rich beverages has increased too. For example, catechin compound(s), a type of polyphenols, are known to have a suppression effect on an increase in cholesterol and there are needs for beverages containing catechin compound(s). However, catechin compound(s) have a characteristic bitter taste and astringency and therefore methods for reducing the bitter taste and astringency have been proposed to make such beverages more drinkable. For example, Patent Literature 2 discloses that astringency characteristic of catechin compound(s) can be suppressed by adjusting the glutamic acid concentration in beverages containing catechin compound(s) to a certain range.